Cementitious sheet



June 18, 1935. DORN r L I 2,004,935

CEMENTITIOUS SHEET I v Filed April 28, 1932 2 Sheets-Sheet l l NVENTORS Benz 3011 1/ B MarZzn 37 21/18 ATTORNEYS June 1935. I R, DQRN ET AL I 2,004,935

CEMENTITIOUS SHEET Filed April 28, 1952 2 Sheets-Sheet 2 I INVENTd RS Zehe 1vr J1/ @arlzn Mllzs ATTORNEYS Patented June 18, 1935 UNITED s'm'rss- PATENT OFFICE 17 Claims.

This invention pertains generally to the class of cementitious materials and particularly to the class of cementitious materials which are adapted to be formed for structural purposes. The invention pertains more particularly to sheets made from a pulp comprising a fibrous material and a suitable binder and to the process of manufacturing such sheets.-

For the purposes of illustration, this invention will be described in connection with a pulp made from hydraulic cement, asbestos fibre and water. However, it is to be strictly understood that the invention is in no way limited thereto. It is adapted for use in connection with the manufacture of sheets with a pulp of any character, and particularly pulps containing fibrous fillers.

Sheets manufactured with a composition comprising cement, asbestos fibre and water are quite common in the art. Many of such sheets of the prior art, however, are objectionable, among other things because they are not of uniform density and strength, have high compression areas developed at irregular intervals during manufacture, do not properly incorporate reinforcing members and do not have a strength sufilciently commensurate with the amount of fibrous filler employed. These objections obtain particularly when the sheet has a form other than fiat, that is, such as corrugated, etc.

Furthermore, many of the processes of the prior art involve an inordinate number of steps.

To overcome these difliculties we have provided a process whereby the fibrous material in the finished sheet aifords a substantially increased aid to structural strength. This is accomplished, first, by forming the sheet in a manner such that at least a large part of the fibrous material isoriented into planes more or less parallel to the surface as opposed to a vertical or a heterogeneous arrrangement, and second, by depositing the pulp in a manner so that it imme diately takes the general form of the finished sheet, thus avoiding the stresses of molding and corrugating which tend to bend and disturb the relationship of the fibres at various points, and

tend to develop high compression areas at irregular intervals resulting in variation in density. Furthermore, when reinforcing members such as rods. mesh, expanded metal, etc., are incorporat-- ed, this is done'at a time and in a manner so that a the pulp can entirely surround and impound all forcing member having the form which it will assume in the finished sheet at the time of its incorporation. A complete union is thus afforded between the pulp and the reinforcing materials. Moreover, by building upa sheet by way of laminations, it is possible to orient the fibres 5 throughout the section, thus very substantially increasing the structural strength of the sheet per unit of fibrous material employed. This also makes it possible to vary the amount of fibrous material across a section in accordance with the 10 nature and distribution of stresses across said section when the sheet is in use.

Inasmuch as the novel product has very definite characteristics which result from the novel steps of the process, we often prefer to incorporate with the. laminations means for identifying our product from those of the prior art by a mere examination of a section thereof. This means comprises a deposit between lamlnations of a .thin sheet, stripe, or stripes, of a coloring material. This coloring material very definitely demonstrates the position of each lamination in the finished sheet and will definitely show whether or not there has been a substantial disturbance in the structural relationship of the materials comprising the laminations in the process of manufacture. I

Furthermore, the steps in our process are simple and few in number.

These features of our invention will become more obvious upon referenceto the drawings, in which Figure 1 is a diagrammatic illustration of apparatus for carrying out our process;-

Figure 2 is a perspective view of a matrix;

Figure 3 is a broken section of a matrix with a layer of pulp thereon;

Figure 4 is a broken section of a finished laminated sheet;

Figure 5 is a broken section of a finished laminated sheet illustrating the identifying means as well as one type of reinforcing member; and

Figure 6 is a broken section of a finished laminated sheet illustrating another type of reinforcing member.

Refen'ing more particularly to the drawings, at In is shown a conveyor which may be of any approved construction and type and is shown as of the driven roller type merely for the purposes of illustration. Resting upon the conveyor I0 is showna matrix 'I I. Matrix II has an upper surface I! conforming to that of the finished sheet whether of flat or of corrugated or of any other sectional configuration. Matrix ll is illustrated as passing-under a hopper i3 containing pulp 5 a the side wall 5| at the slot l5.

' illustrated at I. Hopper I! may be of any de- The function of hopper I3 is that of depositing a layer It of pulp on the matrix H. In the hopper shown this is accomplished by means of a slot I5. This hopper comprises oppositely arranged reciprocating side walls 50 and 5| shown arranged in the form of a V with the opening or slot l5 at the vertex. Side walls 50 and 5| are arranged between stationary end walls 53, the side walls 50 and 5! being supported in guides 54 secured to the end walls 53. Side wall 50 is illustrated as being somewhat longer than The side wall 50 thus acts somewhat as a base toward which the side wall 5| may operate in the formation of a layer. Any means may be provided for reciprocating side walls 50 and 5| such as eccentrics, etc. This construction is more particularly described in our copending application. The layer 16 may be of uniform sectional thickness or, if

desired, may vary in sectional thickness transversely of the sheet. For instance, the latter might be desired when surface It is corrugated to obtain an increased thickness at eitherthe crests or the vales, or both, and might be accomplished by varying the contour of slot 15 to give to the layer IS the sectional form desired.

Preferably the pulp I4 is made up with a minimum water content so that it will be unnecessary to drain or expel any water from the layer or layers prior to the final pressing step.- For instance, the mass may be of such a viscous, pasty consistency as to require some special means to cause the desired fiow through the slot l5, such as a vibrating hopper, a particular form of which is disclosed in our copending application above referred to, or such as a positive pressure on the pulp II. to extrude it through the slot l5, etc.

The layer It by virtue of itsfiow through slot l5 will have at least a large part of its fibrous material oriented so that the individuai fibres will become more or less substantially parallel to the surfaces of the layer It. That is, in the case of a corrugated sheet, a large part of the 'fibre will be orientated into planes more or less horizontal or parallel to the axes of the corrugations as opposed to a vertical or a heterogeneous arrangement.- In other words, at least a large part of the fibrous material is arranged in directions longitudinally and transversely of the layer I6 instead of in the direction of the thickness of the sheet. This orientation is not disturbed as the layer It conforms itself to the surface l2 of the matrix II.

The applying of the layer ii to the matrix H is a continuous process, the matrix moving to the right in Figure 1 as indicated by the arrow.

The thickness of the layer it fed from'the hopper I 3 through the slot i 5 can be varied, for instance, by varying the'speed of vibration of the hopper or varying the pressure on the pulp as the case may be, by varying the opening at the slot l5, by varying the water ratio of the pulp composition, by varying the speed of the matrix H, etc.

Adjacent to the hopper I! we have illustrated a smoothing roller it which performs thefunction of smoothing out any minute undulations which might occur on-the upper surface of the layer It. It is, of course, understood that the roller i8 conforms to the surface which layer l5 has assumed after its deposit on the matrix H, be this flat, corrugated or otherwise. Roller J8 preferably travels oppositely to the layer 15 at.

anincreased peripheral speed, and only lightly touches layer IS. A shoe might be substituted for the roller It or the roller 18 or its equivalent might.be entirely eliminated as desired.

As the matrix H with its layer it passes under the color depositing device shown generally at IS, a thin layer ll of any suitable coloring'medium might be deposited on layer I 6 such as a mixture of hydraulic cement and 10% red iron oxide. This film may be either in sheet or stripe form, and in any event is preferably very fine, its purpose being merely to define the border line between laminations as above set forth.

The device I! may be of any approved construction.

If the sheet is to be made of lamina'tions, a. second layer 20 is deposited upon the layer l5 by hopper 2i as illustrated in dotted lines. The layer 20 will conform to the surface of the layer It and may be of like thickness or otherwise as desired. v

The consistency and/or composition of the pulp 22 in hopper 21 may be similar to that of the pulp I or may be varied. Variation of fibre content is particularly beneficial in the formation of a laminated sheet which is to be used for roofing and similar purposes wherein the load is carried by one surface of the sheet only or where the load on one surface is greater than that on the other.

For instance, the layer under tension may have a v higher fibre content to add strength under tension, because the tensile strength of materials of this type is generally considerably lower than the compressive strength. In this instance the layer under compression may have a considerably less fibre content, not only because it is placed under compression and, therefore, does not need the same amount of added fibre to have the same strength as the'layer under tension, but also so that it may have a more highly compacted and impervious surface exposed to the weather.

For instance, in a two-layer laminated sheet we findthat the upper layerwhich is exposed to the weather may have 20% less fibre content without impairing the strength of the sheet.

This at the same time greatly improves the resistance of the sheet to the elements.

' It is, of course, understood that a sheet may be made'up of' any number of laminations and the fibre content may be. varied across the section as desired or may be held .constant.

A smoothing roller 23 in all respects similar to roller It may be added adjacent hopper 2| if desired.

The layer-or layers eventually reach the press 25 comprising an upper matrix 26 anda lower matrix 21 for compacting the sheet. The function of the press 25 is that of expelling the small amount of water present and that of substantially uniform section reduction, thereby bringing about intimate contact of the particles. This is accomplished without a substantial disturbance of' the relationsh p of the particles, without substantial displacement of material laterally and without setting up high pressure zones at irregu-, lar places throughout the area. The surface of matrix 26, of course, conforms more or less closely to the upper surface of the sheet.' Provision is made in or about matirx 21 for the removal of water expelled from the sheet. Matrix may be perforated for this purpose if desired or may comprise any other form of filter bed to permit escape of water during pressing.

A corrugated matrix 23, having perforations 29, is shown in perspective in Figure 2.

After the water has been expelled as above set forth, the matrix and sheet are removed from the press and the sheet may be stripped immediately from the matrix or may be allowed to cure thereon. The process is now substantially completed and the finished sheet after curing may be further processed as desired and as is usual in the art.

In Figure 3 is illustrated a sheet 30 comprising a single lamination resting upon a perforated corrugated matrix 3 I. It should be noted that sheet 30 has thickened crests and vales, a configuration described in copending application Serial No. 447,150 of Martin Willis and Frederick Schroder. v

In Figure 4 is illustrated a finished sheet 32 comprising laminations 33 and 34. At 35 is shown a thin film of coloring material illustrating the dividing line between the laminations.

Incidentally, the slight irregularity in the cross sectional contour of the film 35 resulted during the laying of the layer 33 on the layer 34 and is not the result of the pressing step. The film 35 not only clearly demonstrates that there is not a substantial disturbance of the relationship of the fibres in applicants process but also affords a ready means. of identification of materials resulting from said process in view of the substantial non-disturbance of the contour of the film 35.

In Figure is shown a broken section of a finished sheet 31 comprising upper lamination 38 and lower lamination 39 with an intermediate film 40. The sheet 31 has reinforced vales, said vales being reinforced by longitudinally arranged rods 4| positioned in the vales between layers 38 and 39.

To thus incorporate the rods 4| between layers 38 and 39, rods 4| are placed in the vales upon layer 39 between hoppers I3 and 2|, that is, before the application-of layer 38. It should be noted that the rods 4| have not been'changed in contour, bent or reshaped in any way by the press 25. I

In Figure 6 is shown a broken section of a corrugated sheet 43 comprising upper layer 44 and lower layer 45. of mesh 46 such as wire cloth, expandedmetal. etc. The corrugated rnesh 46 was incorporated in the sheet 43 between hoppers |3and 2|,-the mesh having been preformed to the shape which it assumes in Figure 6, said :mesh'46 not having been changed in contour by the press 25.

If desired, rods 4| shown in Figure 5 may be added to the vales of sheet 43 or to the crests or to both. 1

It is, .of course, understood that in sheet 31 rods 4| might be moved to the crests or'may be placed in both the crests and the vales.

It will be seen from the above description that the material forming the sheet immediately assumes the general shape which it is to have in the matrix I I.

Sheet 43 is reinforced by a sheet While we prefer to apply the pulp to the matrix H in sheet form and/or with the fibres oriented. it is, of course, understood that the inventionis not limited thereto inasmuch as substantial advantages accrue by way of simplicity of i'orma-v tion of a sheet and by way of avoiding undue disturbance of the structural relationship of the filler and binder such as absence of bending, etc. during the formation of the sheet.

' While we have described a single matrix II on the conveyor III, it is, of course, understood that any number of matrices M may succeed each other, for instance in abutting relation,-and may be connected together if desired to make a continuous sectional apron, the layers from hoppers I3 and/ or 2|, etc. being applied continuously and being severed at the-end of each matrix when the matrix is disconnected from the apron for placing in the press 25. Means might be provided for continuously expelling water from the sheets.

It will be seen that by varying the fibre content across the section of a sheet, the fibre content may be materially reduced without a sacrifice of strength and the product will have a substantially increased resistance to the elements.

It will also be seen that a substantial saving in fibre is efiected without sacrifice in strength b orientation of the fibre.

The preforming of the reinforcing members and the time of their incorporation in the sheet insures a complete impounding of all of the surfaces of ,the reinforcement members and a firm union'between the reinforcement members and the remaining materials.

It is, of course, obvious that the reinforcement I members may be smooth or have any other surface contour.

The term sheet" is used herein in its broad sense to cover not only the structural members that are sold as sheets but also to cover other members that are generally of sheetlike form, such as tiles, shingles, etc.

. Having described our invention, it is obvious terials in which the finished sheet has its fibres so oriented that the direction component parallel to the surfaces of the sheet is greater than the direction component perpendicular to the surfaces thereof, and the fibres are undisturbed from their initially deposited position, whereby the sheet is relatively free from internal stresses and has a high structural strength.

3. A corrugated structural sheet made from a pulp containing cementitious and fibrous mate rials in which the finished sheet has substantially the same form of cross section as that in which the'pulp was deposited andhas at least alarge part of its fibres so oriented that the direction component parallel to the surfaces of the sheet is greater than the direction component perpendicular to the surfaces thereof, whereby the parallel fibres are undisturbedltheshe'et is high structural strength, saidsheet having a substantially uniform density resulting from a substantially uniform section reduction.

4. A corrugated structural sheet made from a pulp containing hydraulic cement and asbestos fibres in which the finished sheet has substantiallythe same form of cross section as that in which the pulp was deposited and has at least a large part of its fibres so oriented. that the direction component parallel to the surfaces of the sheet is greater than the direction component perpendicular to the surfaces thereof, whereby the parallel fibres are undisturbed, the sheet is relatively free from'internal stresses and has a high structural strength.

5. A corrugated structural sheet made from a pulp containing cementitious and fibrous materials in which the finished corrugated sheet has substantially the same form of cross section as that in which the pulp was deposited and has at least a large part of its fibres so oriented that the direction component parallel to the surfaces of the sheet is greater than the direction component perpendicular to the surfaces thereof, whereby the sheet is relatively free from internal stresses and has a high structural strength.

6. A corrugated structural sheet made from a pulp containing cementitious and fibrous materials in which the finished corrugated sheet has substantially the same form of cross section as that in which the pulp was deposited and has at least a large part of its fibres so oriented that the direction component parallel to the surfaces of the sheet is greater than the direction component perpendicular to the surfaces thereof, whereby the sheet is relatively free from internal stresses and has a high structural strength, said sheet having a substantially uniform density resulting from a substantially uniform section reduction.

7. A corrugated structural sheet comprising a plurality of joined laminations each made from a pulp containing cementitious and fibrous materials in which the form of the cross section of the finished sheet is substantially the same as that in which the pulp was deposited and has at least a large'part of its fibres so oriented thatthe direction component parallel to the surfaces of the sheet is greater than the direction component perpendicular to the'surfaces thereoi, whereby the fibres of the sheet are undisturbed, the sheet is relatively free from internal stresses and has ahigh structural strength.

8. A structural sheet comprising a plurality of joined laminations each made from a pulp containing cementitious and fibrous materials in which the finished sheet has substantially the form in which the pulp was deposited and has at least a large part of its fibres so oriented that the direction component parallel to the surfaces of the sheet is greater than the direction component perpendicular to the surfaces thereof, whereby the sheet is relatively free from internal stresses and has-a high structural strength, the fibre content of one of said laminations being substantially greater than the fibrecontent of another of said laminations.

9. A corrugated structural sheet comprising a plurality of joined laminations each made from a pulp containing hydraulic cement and asbestos fibres inwhich the finished sheet has its fibres so oriented that the direction component parallel to the surfaces of the sheet is greater than the direction component perpendicular to the sur- /2,004,985 relatively free from internal stresses and has a faces thereof, and the fibres are undisturbed from their initially deposited position, whereby the sheet is relatively free from internal stresses and has a high structural strength;

10. A corrugated structural sheet comprising a plurality of joined laminations each made from a pulp containing hydraulic cement and asbestos fibres in which the finished sheet has its fibres so oriented that the direction component parallel to the surfaces of the sheet is greater than the direction component perpendicular to the surfaces thereof, and the fibres are undisturbed from their initially deposited position, whereby the sheet is relatively free from internal stresses and has a high structural strength, the fibre content of one of said laminations being substantially greater than the fibre content of another of said laminations.

11. A corrugated structural sheet comprising a plurality of joined laminations each made from a pulp containing hydraulic cement and asbestos fibres in which the finished sheet has substantially the form in which the pulp was deposited and has at least a large part of its fibres so oriented that the direction component parallel to the surfaces of the sheet is greater than the direction component perpendicular to the surfaces thereof, whereby the sheet is relatively free from internal stresses and has a high structural strength, the fibre content of one of said laminations being substantially greater than the fibre content of another of said laminations.

12. A structural sheet having a surface portion of non-planar contour and comprising a, plurality of joined laminations each made from a pulp containing cementitious and fibrous materials in which the finished sheet has substantially the form in which the pulp was deposited and has at least. a large part of its fibres so oriented that the direction component parallel to the surfaces of the sheet is greaterthan the direction component perpendicular to the surfaces thereof, said sheet having reinforcing members disposed between and joined to two adjacent laminations,

'said reinforcing members conforming to the shape of said finished sheet at the time of incorporation between the laminations thereof, whereby the sheet is relatively free from internal stresses and has a high structural strength.

13. A structural sheet having a surface portion of non-planar contour and comprising a plurality of Joined laminations each made from a pulp containing cementitious and fibrous-materials in which the finished sheet has substantially the form in which'the pulp was deposited and has at least a a ge part of its fibres so oriented that the direction component parallel to the surfaces of the sheet is greater than the direction component perpendicular to the surfaces thereof, said.

sheet having reinforcing members disposed between and joined to two adjacent laminations, said reinforcing members conforming to the shape of said finished sheet at the time of incorporationbetween the laminations thereof, whereby the sheet is relatively free from internal stresses and has a high structural strength, the fibre content of one of said laminations being substantially ater than the fibre content of another of said laminations.

14. A corrugated structural sheet comprising a plurality of Joined laminations each made from a pulp containing cementitious and fibrous materials in which the form of the cross section of the finished sheet is substantially the same as that in which the pulp was deposited, said sheet having reinforcing members disposed in the vales of the corrugations of said sheet between and joined to two adjacent laminations, said sheet further having a substantially uniform density resulting from a substantially uniform section reduction. 15. A corrugated structural sheet comprising a plurality of joined laminations made from acementitious pulp, said sheet having reinforcing members disposed in and extending lengthwise of the vales of the corrugations of said sheet between and joined to two adjacent laminations, and said reinforcing members having all of their surfaces impounded by and in contacting relation with said laminations, whereby said reinforcing members are protected from contact with air and moisture and impart high structural strength to said sheet.

16. A corrugated structural sheet comprising a containing cementitious and fibrous materials, said sheet having reinforcing means disposed between and joined to two adjacent laminations, and extending at least partly transversely of said corrugations, said reinforcing means conforming to the shape of said finished sheet at the time of incorporation between the laminations thereof and being substantially free from deformation resulting from stresses imposed in the process of manufacture of said sheet.

1'7. A structural sheet having a surface portion of non-planar contour and made from a pulp containing cementitious and fibrous material in which-the pulp and the contained fibres are undisturbed from their initially deposited position and the sheet has a substantially uniform density resulting from a substantially uniform section reduction.

plurality of joined laminations made from a pulp RENE DORN. MAR'I'IN WILLIS. 

